Installation Manual

Chapter 7 Best Practices: Installation & Troubleshooting
In this section are Motorola recommended vehicle installation practices that can address or prevent
many issues, including:
• Radio circuit damage due to over voltage condition
• Radio/Accessories "lock up"
• Radio/Accessories change state/lock-up when radio PTT is depressed
• Radio powers up in the FL 01/90 state (general communication error code)
• Radio intermittently resets
• Radio loses secure key
• Transmit audio distortion on motorcycle radio when engine is running
• Keypad buttons become inoperative for motorcycle radios when engine is running
• Alternator whine present when transmitting with engine running
• Radio/Accessories turn themselves on/off
7.1 Check Wiring of Ignition and Radio Ignition Sensing
• If it is required to turn the radio on and off via the ignition sense switch, in addition to the control
head’s on/off switch, connect the ignition sense lead to the accessory terminal from the ignition
switch (usually in the vehicle’s fuse panel under accessory or radio).
NOTE: Motorola Solutions recommends protecting or isolating the radio’s ignition sense input from
voltage spikes in excess of +/- 40VDC. Such spikes can be hundreds of volts in amplitude and
are common in larger vehicles (utility trucks, buses and etc.), especially when the source is
common to a solenoid coil. A triggerable oscilloscope is required to determine the existence of
such spikes as most voltmeters cannot measure in short duration (< 1 msec). If the condition of
the intended ignition sense source is unknown, Motorola Solutions recommends isolating the
source from the radio with a relay or the use of a suppression diode wired between the source
and ground. Any high current suppression diode (i.e. MR2535) with a breakdown voltage of
between 18 and 40 volts will suffice. A suitable diode kit is available from Motorola Solutions
parts, kit number HLN6325_.
• If it is required to have the radio power up only via the control head’s on/off switch, then connect
the ignition sense lead directly to the positive terminal of the battery. This will mean the ignition
sense will always be ignored and a re-wiring will be necessary in the future if the operator
chooses any ignition sense CPS setting.
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